RFR: 8327999: Remove copy of unused registers for cpu features check in x86_64 AVX2 Poly1305 implementation

[Srinivas Vamsi Parasa]

The goal of this PR is to fix the bug reported in #17881 where data from unused registers (rbx, rcx, rdx) is being copied.

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Commit messages:
 - 8327999: Remove copy of unused registers for cpu features check in x86_64 AVX2 Poly1305 implementation

Changes: https://git.openjdk.org/jdk/pull/18248/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18248&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327999
  Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18248.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18248/head:pull/18248

PR: https://git.openjdk.org/jdk/pull/18248